I have only 3 red and blue Columbians and one is a bully to the rest of my community tank. If I get 3-4 more, will they stop being so aggressive and piggish. They are the fastest and eat all the food! . Having trouble getting more. I have one diamond, 7 neons and 3 black skirts (these are aggressive too). I want a peaceful tank; I have a 32 gallon tall hexagon I inherited. Ideally, I'd like top column, middle and bottom dwellers. Should I give away my columbians and black skirts and start over? I was thinking 6 diamonds, keeping my neons, and... suggestions for top dwellers? Black neons? silver hatches? Harlequin rasboras? I'd like some color.